fs/nilfs2/namei.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * NILFS pathname lookup operations.
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Modified for NILFS by Amagai Yoshiji and Ryusuke Konishi.
   8  */
   9 /*
  10  *  linux/fs/ext2/namei.c
  11  *
  12  * Copyright (C) 1992, 1993, 1994, 1995
  13  * Remy Card (card@masi.ibp.fr)
  14  * Laboratoire MASI - Institut Blaise Pascal
  15  * Universite Pierre et Marie Curie (Paris VI)
  16  *
  17  *  from
  18  *
  19  *  linux/fs/minix/namei.c
  20  *
  21  *  Copyright (C) 1991, 1992  Linus Torvalds
  22  *
  23  *  Big-endian to little-endian byte-swapping/bitmaps by
  24  *        David S. Miller (davem@caip.rutgers.edu), 1995
  25  */
  26
  27 #include <linux/pagemap.h>
  28 #include "nilfs.h"
  29 #include "export.h"
  30
  31 #define NILFS_FID_SIZE_NON_CONNECTABLE \
  32         (offsetof(struct nilfs_fid, parent_gen) / 4)
  33 #define NILFS_FID_SIZE_CONNECTABLE      (sizeof(struct nilfs_fid) / 4)
  34
  35 static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode)
  36 {
  37         int err = nilfs_add_link(dentry, inode);
  38
  39         if (!err) {
  40                 d_instantiate_new(dentry, inode);
  41                 return 0;
  42         }
  43         inode_dec_link_count(inode);
  44         unlock_new_inode(inode);
  45         iput(inode);
  46         return err;
  47 }
  48
  49 /*
  50  * Methods themselves.
  51  */
  52
  53 static struct dentry *
  54 nilfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
  55 {
  56         struct inode *inode;
  57         ino_t ino;
  58
  59         if (dentry->d_name.len > NILFS_NAME_LEN)
  60                 return ERR_PTR(-ENAMETOOLONG);
  61
  62         ino = nilfs_inode_by_name(dir, &dentry->d_name);
  63         inode = ino ? nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino) : NULL;
  64         return d_splice_alias(inode, dentry);
  65 }
  66
  67 /*
  68  * By the time this is called, we already have created
  69  * the directory cache entry for the new file, but it
  70  * is so far negative - it has no inode.
  71  *
  72  * If the create succeeds, we fill in the inode information
  73  * with d_instantiate().
  74  */
  75 static int nilfs_create(struct user_namespace *mnt_userns, struct inode *dir,
  76                         struct dentry *dentry, umode_t mode, bool excl)
  77 {
  78         struct inode *inode;
  79         struct nilfs_transaction_info ti;
  80         int err;
  81
  82         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
  83         if (err)
  84                 return err;
  85         inode = nilfs_new_inode(dir, mode);
  86         err = PTR_ERR(inode);
  87         if (!IS_ERR(inode)) {
  88                 inode->i_op = &nilfs_file_inode_operations;
  89                 inode->i_fop = &nilfs_file_operations;
  90                 inode->i_mapping->a_ops = &nilfs_aops;
  91                 nilfs_mark_inode_dirty(inode);
  92                 err = nilfs_add_nondir(dentry, inode);
  93         }
  94         if (!err)
  95                 err = nilfs_transaction_commit(dir->i_sb);
  96         else
  97                 nilfs_transaction_abort(dir->i_sb);
  98
  99         return err;
 100 }
 101
 102 static int
 103 nilfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 104             struct dentry *dentry, umode_t mode, dev_t rdev)
 105 {
 106         struct inode *inode;
 107         struct nilfs_transaction_info ti;
 108         int err;
 109
 110         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 111         if (err)
 112                 return err;
 113         inode = nilfs_new_inode(dir, mode);
 114         err = PTR_ERR(inode);
 115         if (!IS_ERR(inode)) {
 116                 init_special_inode(inode, inode->i_mode, rdev);
 117                 nilfs_mark_inode_dirty(inode);
 118                 err = nilfs_add_nondir(dentry, inode);
 119         }
 120         if (!err)
 121                 err = nilfs_transaction_commit(dir->i_sb);
 122         else
 123                 nilfs_transaction_abort(dir->i_sb);
 124
 125         return err;
 126 }
 127
 128 static int nilfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 129                          struct dentry *dentry, const char *symname)
 130 {
 131         struct nilfs_transaction_info ti;
 132         struct super_block *sb = dir->i_sb;
 133         unsigned int l = strlen(symname) + 1;
 134         struct inode *inode;
 135         int err;
 136
 137         if (l > sb->s_blocksize)
 138                 return -ENAMETOOLONG;
 139
 140         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 141         if (err)
 142                 return err;
 143
 144         inode = nilfs_new_inode(dir, S_IFLNK | 0777);
 145         err = PTR_ERR(inode);
 146         if (IS_ERR(inode))
 147                 goto out;
 148
 149         /* slow symlink */
 150         inode->i_op = &nilfs_symlink_inode_operations;
 151         inode_nohighmem(inode);
 152         inode->i_mapping->a_ops = &nilfs_aops;
 153         err = page_symlink(inode, symname, l);
 154         if (err)
 155                 goto out_fail;
 156
 157         /* mark_inode_dirty(inode); */
 158         /* page_symlink() do this */
 159
 160         err = nilfs_add_nondir(dentry, inode);
 161 out:
 162         if (!err)
 163                 err = nilfs_transaction_commit(dir->i_sb);
 164         else
 165                 nilfs_transaction_abort(dir->i_sb);
 166
 167         return err;
 168
 169 out_fail:
 170         drop_nlink(inode);
 171         nilfs_mark_inode_dirty(inode);
 172         unlock_new_inode(inode);
 173         iput(inode);
 174         goto out;
 175 }
 176
 177 static int nilfs_link(struct dentry *old_dentry, struct inode *dir,
 178                       struct dentry *dentry)
 179 {
 180         struct inode *inode = d_inode(old_dentry);
 181         struct nilfs_transaction_info ti;
 182         int err;
 183
 184         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 185         if (err)
 186                 return err;
 187
 188         inode->i_ctime = current_time(inode);
 189         inode_inc_link_count(inode);
 190         ihold(inode);
 191
 192         err = nilfs_add_link(dentry, inode);
 193         if (!err) {
 194                 d_instantiate(dentry, inode);
 195                 err = nilfs_transaction_commit(dir->i_sb);
 196         } else {
 197                 inode_dec_link_count(inode);
 198                 iput(inode);
 199                 nilfs_transaction_abort(dir->i_sb);
 200         }
 201
 202         return err;
 203 }
 204
 205 static int nilfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 206                        struct dentry *dentry, umode_t mode)
 207 {
 208         struct inode *inode;
 209         struct nilfs_transaction_info ti;
 210         int err;
 211
 212         err = nilfs_transaction_begin(dir->i_sb, &ti, 1);
 213         if (err)
 214                 return err;
 215
 216         inc_nlink(dir);
 217
 218         inode = nilfs_new_inode(dir, S_IFDIR | mode);
 219         err = PTR_ERR(inode);
 220         if (IS_ERR(inode))
 221                 goto out_dir;
 222
 223         inode->i_op = &nilfs_dir_inode_operations;
 224         inode->i_fop = &nilfs_dir_operations;
 225         inode->i_mapping->a_ops = &nilfs_aops;
 226
 227         inc_nlink(inode);
 228
 229         err = nilfs_make_empty(inode, dir);
 230         if (err)
 231                 goto out_fail;
 232
 233         err = nilfs_add_link(dentry, inode);
 234         if (err)
 235                 goto out_fail;
 236
 237         nilfs_mark_inode_dirty(inode);
 238         d_instantiate_new(dentry, inode);
 239 out:
 240         if (!err)
 241                 err = nilfs_transaction_commit(dir->i_sb);
 242         else
 243                 nilfs_transaction_abort(dir->i_sb);
 244
 245         return err;
 246
 247 out_fail:
 248         drop_nlink(inode);
 249         drop_nlink(inode);
 250         nilfs_mark_inode_dirty(inode);
 251         unlock_new_inode(inode);
 252         iput(inode);
 253 out_dir:
 254         drop_nlink(dir);
 255         nilfs_mark_inode_dirty(dir);
 256         goto out;
 257 }
 258
 259 static int nilfs_do_unlink(struct inode *dir, struct dentry *dentry)
 260 {
 261         struct inode *inode;
 262         struct nilfs_dir_entry *de;
 263         struct page *page;
 264         int err;
 265
 266         err = -ENOENT;
 267         de = nilfs_find_entry(dir, &dentry->d_name, &page);
 268         if (!de)
 269                 goto out;
 270
 271         inode = d_inode(dentry);
 272         err = -EIO;
 273         if (le64_to_cpu(de->inode) != inode->i_ino)
 274                 goto out;
 275
 276         if (!inode->i_nlink) {
 277                 nilfs_warn(inode->i_sb,
 278                            "deleting nonexistent file (ino=%lu), %d",
 279                            inode->i_ino, inode->i_nlink);
 280                 set_nlink(inode, 1);
 281         }
 282         err = nilfs_delete_entry(de, page);
 283         if (err)
 284                 goto out;
 285
 286         inode->i_ctime = dir->i_ctime;
 287         drop_nlink(inode);
 288         err = 0;
 289 out:
 290         return err;
 291 }
 292
 293 static int nilfs_unlink(struct inode *dir, struct dentry *dentry)
 294 {
 295         struct nilfs_transaction_info ti;
 296         int err;
 297
 298         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 299         if (err)
 300                 return err;
 301
 302         err = nilfs_do_unlink(dir, dentry);
 303
 304         if (!err) {
 305                 nilfs_mark_inode_dirty(dir);
 306                 nilfs_mark_inode_dirty(d_inode(dentry));
 307                 err = nilfs_transaction_commit(dir->i_sb);
 308         } else
 309                 nilfs_transaction_abort(dir->i_sb);
 310
 311         return err;
 312 }
 313
 314 static int nilfs_rmdir(struct inode *dir, struct dentry *dentry)
 315 {
 316         struct inode *inode = d_inode(dentry);
 317         struct nilfs_transaction_info ti;
 318         int err;
 319
 320         err = nilfs_transaction_begin(dir->i_sb, &ti, 0);
 321         if (err)
 322                 return err;
 323
 324         err = -ENOTEMPTY;
 325         if (nilfs_empty_dir(inode)) {
 326                 err = nilfs_do_unlink(dir, dentry);
 327                 if (!err) {
 328                         inode->i_size = 0;
 329                         drop_nlink(inode);
 330                         nilfs_mark_inode_dirty(inode);
 331                         drop_nlink(dir);
 332                         nilfs_mark_inode_dirty(dir);
 333                 }
 334         }
 335         if (!err)
 336                 err = nilfs_transaction_commit(dir->i_sb);
 337         else
 338                 nilfs_transaction_abort(dir->i_sb);
 339
 340         return err;
 341 }
 342
 343 static int nilfs_rename(struct user_namespace *mnt_userns,
 344                         struct inode *old_dir, struct dentry *old_dentry,
 345                         struct inode *new_dir, struct dentry *new_dentry,
 346                         unsigned int flags)
 347 {
 348         struct inode *old_inode = d_inode(old_dentry);
 349         struct inode *new_inode = d_inode(new_dentry);
 350         struct page *dir_page = NULL;
 351         struct nilfs_dir_entry *dir_de = NULL;
 352         struct page *old_page;
 353         struct nilfs_dir_entry *old_de;
 354         struct nilfs_transaction_info ti;
 355         int err;
 356
 357         if (flags & ~RENAME_NOREPLACE)
 358                 return -EINVAL;
 359
 360         err = nilfs_transaction_begin(old_dir->i_sb, &ti, 1);
 361         if (unlikely(err))
 362                 return err;
 363
 364         err = -ENOENT;
 365         old_de = nilfs_find_entry(old_dir, &old_dentry->d_name, &old_page);
 366         if (!old_de)
 367                 goto out;
 368
 369         if (S_ISDIR(old_inode->i_mode)) {
 370                 err = -EIO;
 371                 dir_de = nilfs_dotdot(old_inode, &dir_page);
 372                 if (!dir_de)
 373                         goto out_old;
 374         }
 375
 376         if (new_inode) {
 377                 struct page *new_page;
 378                 struct nilfs_dir_entry *new_de;
 379
 380                 err = -ENOTEMPTY;
 381                 if (dir_de && !nilfs_empty_dir(new_inode))
 382                         goto out_dir;
 383
 384                 err = -ENOENT;
 385                 new_de = nilfs_find_entry(new_dir, &new_dentry->d_name, &new_page);
 386                 if (!new_de)
 387                         goto out_dir;
 388                 nilfs_set_link(new_dir, new_de, new_page, old_inode);
 389                 nilfs_mark_inode_dirty(new_dir);
 390                 new_inode->i_ctime = current_time(new_inode);
 391                 if (dir_de)
 392                         drop_nlink(new_inode);
 393                 drop_nlink(new_inode);
 394                 nilfs_mark_inode_dirty(new_inode);
 395         } else {
 396                 err = nilfs_add_link(new_dentry, old_inode);
 397                 if (err)
 398                         goto out_dir;
 399                 if (dir_de) {
 400                         inc_nlink(new_dir);
 401                         nilfs_mark_inode_dirty(new_dir);
 402                 }
 403         }
 404
 405         /*
 406          * Like most other Unix systems, set the ctime for inodes on a
 407          * rename.
 408          */
 409         old_inode->i_ctime = current_time(old_inode);
 410
 411         nilfs_delete_entry(old_de, old_page);
 412
 413         if (dir_de) {
 414                 nilfs_set_link(old_inode, dir_de, dir_page, new_dir);
 415                 drop_nlink(old_dir);
 416         }
 417         nilfs_mark_inode_dirty(old_dir);
 418         nilfs_mark_inode_dirty(old_inode);
 419
 420         err = nilfs_transaction_commit(old_dir->i_sb);
 421         return err;
 422
 423 out_dir:
 424         if (dir_de) {
 425                 kunmap(dir_page);
 426                 put_page(dir_page);
 427         }
 428 out_old:
 429         kunmap(old_page);
 430         put_page(old_page);
 431 out:
 432         nilfs_transaction_abort(old_dir->i_sb);
 433         return err;
 434 }
 435
 436 /*
 437  * Export operations
 438  */
 439 static struct dentry *nilfs_get_parent(struct dentry *child)
 440 {
 441         unsigned long ino;
 442         struct inode *inode;
 443         struct nilfs_root *root;
 444
 445         ino = nilfs_inode_by_name(d_inode(child), &dotdot_name);
 446         if (!ino)
 447                 return ERR_PTR(-ENOENT);
 448
 449         root = NILFS_I(d_inode(child))->i_root;
 450
 451         inode = nilfs_iget(child->d_sb, root, ino);
 452         if (IS_ERR(inode))
 453                 return ERR_CAST(inode);
 454
 455         return d_obtain_alias(inode);
 456 }
 457
 458 static struct dentry *nilfs_get_dentry(struct super_block *sb, u64 cno,
 459                                        u64 ino, u32 gen)
 460 {
 461         struct nilfs_root *root;
 462         struct inode *inode;
 463
 464         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO)
 465                 return ERR_PTR(-ESTALE);
 466
 467         root = nilfs_lookup_root(sb->s_fs_info, cno);
 468         if (!root)
 469                 return ERR_PTR(-ESTALE);
 470
 471         inode = nilfs_iget(sb, root, ino);
 472         nilfs_put_root(root);
 473
 474         if (IS_ERR(inode))
 475                 return ERR_CAST(inode);
 476         if (gen && inode->i_generation != gen) {
 477                 iput(inode);
 478                 return ERR_PTR(-ESTALE);
 479         }
 480         return d_obtain_alias(inode);
 481 }
 482
 483 static struct dentry *nilfs_fh_to_dentry(struct super_block *sb, struct fid *fh,
 484                                          int fh_len, int fh_type)
 485 {
 486         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 487
 488         if (fh_len < NILFS_FID_SIZE_NON_CONNECTABLE ||
 489             (fh_type != FILEID_NILFS_WITH_PARENT &&
 490              fh_type != FILEID_NILFS_WITHOUT_PARENT))
 491                 return NULL;
 492
 493         return nilfs_get_dentry(sb, fid->cno, fid->ino, fid->gen);
 494 }
 495
 496 static struct dentry *nilfs_fh_to_parent(struct super_block *sb, struct fid *fh,
 497                                          int fh_len, int fh_type)
 498 {
 499         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 500
 501         if (fh_len < NILFS_FID_SIZE_CONNECTABLE ||
 502             fh_type != FILEID_NILFS_WITH_PARENT)
 503                 return NULL;
 504
 505         return nilfs_get_dentry(sb, fid->cno, fid->parent_ino, fid->parent_gen);
 506 }
 507
 508 static int nilfs_encode_fh(struct inode *inode, __u32 *fh, int *lenp,
 509                            struct inode *parent)
 510 {
 511         struct nilfs_fid *fid = (struct nilfs_fid *)fh;
 512         struct nilfs_root *root = NILFS_I(inode)->i_root;
 513         int type;
 514
 515         if (parent && *lenp < NILFS_FID_SIZE_CONNECTABLE) {
 516                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 517                 return FILEID_INVALID;
 518         }
 519         if (*lenp < NILFS_FID_SIZE_NON_CONNECTABLE) {
 520                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 521                 return FILEID_INVALID;
 522         }
 523
 524         fid->cno = root->cno;
 525         fid->ino = inode->i_ino;
 526         fid->gen = inode->i_generation;
 527
 528         if (parent) {
 529                 fid->parent_ino = parent->i_ino;
 530                 fid->parent_gen = parent->i_generation;
 531                 type = FILEID_NILFS_WITH_PARENT;
 532                 *lenp = NILFS_FID_SIZE_CONNECTABLE;
 533         } else {
 534                 type = FILEID_NILFS_WITHOUT_PARENT;
 535                 *lenp = NILFS_FID_SIZE_NON_CONNECTABLE;
 536         }
 537
 538         return type;
 539 }
 540
 541 const struct inode_operations nilfs_dir_inode_operations = {
 542         .create         = nilfs_create,
 543         .lookup         = nilfs_lookup,
 544         .link           = nilfs_link,
 545         .unlink         = nilfs_unlink,
 546         .symlink        = nilfs_symlink,
 547         .mkdir          = nilfs_mkdir,
 548         .rmdir          = nilfs_rmdir,
 549         .mknod          = nilfs_mknod,
 550         .rename         = nilfs_rename,
 551         .setattr        = nilfs_setattr,
 552         .permission     = nilfs_permission,
 553         .fiemap         = nilfs_fiemap,
 554         .fileattr_get   = nilfs_fileattr_get,
 555         .fileattr_set   = nilfs_fileattr_set,
 556 };
 557
 558 const struct inode_operations nilfs_special_inode_operations = {
 559         .setattr        = nilfs_setattr,
 560         .permission     = nilfs_permission,
 561 };
 562
 563 const struct inode_operations nilfs_symlink_inode_operations = {
 564         .get_link       = page_get_link,
 565         .permission     = nilfs_permission,
 566 };
 567
 568 const struct export_operations nilfs_export_ops = {
 569         .encode_fh = nilfs_encode_fh,
 570         .fh_to_dentry = nilfs_fh_to_dentry,
 571         .fh_to_parent = nilfs_fh_to_parent,
 572         .get_parent = nilfs_get_parent,
 573 };